Was declared,
"To be really serious about mobile operation, I
run an antenna by HiQ that is about 70% efficient at 17 meters and above
and about 36% at 3.8."
That 36% at 3.8 mHz is pretty much wishful thinking. The radiation
resistance of a 'mobile-sized' vertical whip for 75 meters is on order
of 1.0 ohm. Even a ground system composed of 15 radials, each 0.15
wavelength and near the earth, has an equivalent resistance of 15 ohms.
A great center loading coil has probably 3 ohms resistance at best? Add
the 3 ohms to the 15 and divide 1 ohm by that total.
Answer: Overall possible practical mobile antenna system efficiency on
75 meters is limited to approximately 5%. Even this is unlikely to be
achieved.
73, Roy K6XK/0 Iowa
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